Reviewed and updated: 22 October 2026
Keratin tablets are usually hair, skin and nail supplements built around the nutrients your body uses to keep keratin-rich tissues normal, most often biotin, zinc and selenium, rather than tablets of keratin protein itself. A smaller number add hydrolysed keratin, typically made from sheep's wool or feathers.
It is a confusing name, and I understand why people ask. Keratin is the stuff hair and nails are made of, so swallowing keratin sounds logical. The reality is a little different, and once you see how it works, choosing a product gets much easier.
Keratin tablets: the quick answer
- What keratin is: a tough structural protein, the main building material of hair, nails and the outer layer of skin.
- What the tablets usually contain: nutrient formulas, mostly biotin, zinc and selenium, sometimes with hydrolysed keratin added.
- What does the recognised work: biotin, zinc and selenium have recognised roles in maintaining normal hair, skin or nails. Keratin as an ingredient does not.
- Realistic expectations: these nutrients help most where intake has been low, and changes in hair and nails take months, not days.
- One caution: high-dose biotin can interfere with some blood tests, so tell whoever takes your bloods.
Eggs and avocado toast before the day starts. Hair care starts on the plate for me. Illustrative image
First, what keratin actually is
Keratin is a family of fibrous structural proteins. It makes up most of each hair strand and nail, and it forms the tough outer layer of your skin. It is particularly rich in cysteine, a sulphur-containing amino acid that forms cross-links between keratin chains, and those links are what give hair and nails their strength and shape.
The important thing is that your body makes its own keratin, inside the hair follicle and the nail bed, from the protein you eat. To do that normally it needs a steady supply of certain vitamins and minerals. So when we talk about supporting hair and nails, keratin is the end product, not usually the thing in the tablet.
What keratin tablets are made from
Nutrient formulas
Most products sold as keratin tablets are nutrient blends built around biotin, zinc and selenium, sometimes with extras like silica, amino acids or plant extracts. The name is borrowed from the hair-care world because it is instantly recognisable.
Hydrolysed keratin
A smaller group of products contain keratin itself. Because whole keratin is famously hard to digest, it is broken down first into smaller peptides and amino acids, a process called hydrolysis. The raw material is usually sheep's wool or poultry feathers, so these products are not vegan, which is worth checking if that matters to you.
How oral keratin is supposed to work
When you swallow any protein, including hydrolysed keratin, your gut breaks it down into amino acids and small peptides that enter the bloodstream. The theory behind keratin supplements is that these keratin-derived fragments, rich in cysteine, provide useful raw material for the follicle and nail bed. It is a reasonable idea, but it is not the same as keratin travelling intact to your hair. Your body rebuilds keratin from scratch, using the nutrients and amino acids available to it.
Keratin tablets vs salon keratin smoothing
These are entirely different things that happen to share a name. A salon keratin smoothing service is applied to the outside of the hair, then sealed with heat to smooth frizz for a number of weeks. It works on the surface of the hair shaft and does nothing nutritionally. A tablet is swallowed and digested, so it cannot coat your hair in the same way. If you want a smoother finish, that is a salon job. If your interest is nutritional support for normal hair and nails, that is where supplements come in.
Our pick for this guide
Looking for the nutrients that do the recognised work?
10,000mcg biotin, 10mg zinc bisglycinate and 55mcg selenium as selenomethionine per two-tablet serving, vegan. Zinc and selenium contribute to the maintenance of normal hair and nails. A food supplement, not a replacement for medical advice.
From £9.50 · 60 tablets, one month
Shop Biotin Zinc Selenium →The nutrients that actually do the work
Three nutrients have recognised roles directly relevant to hair, skin and nails when provided in a meaningful amount:
- Biotin contributes to the maintenance of normal hair and normal skin.
- Zinc contributes to the maintenance of normal hair, normal nails and normal skin.
- Selenium contributes to the maintenance of normal hair and normal nails.
Notice the word normal. These nutrients support the everyday maintenance of these tissues. They are not a promise of dramatic change, and I would be wary of any product that suggests otherwise. For a deeper look at each, our pillar guide to the best vitamins for hair, skin and nails sets out the full picture.
Does keratin itself have a recognised hair role?
No, and this is the honest heart of the matter. When a keratin-based hair formula was assessed by European food safety scientists in 2012, the panel concluded that a cause-and-effect relationship with maintaining normal hair had not been established. That is why a well-built hair and nail formula leans on biotin, zinc and selenium, whose roles are established, rather than on the keratin name.
What the research on oral keratin shows
There is some direct research, and it deserves a fair reading. A randomised, double-blind, placebo-controlled study by Tursi and colleagues gave healthy women a feather-derived keratin hydrolysate at 500 or 1,000 mg a day for 90 days and reported improvements in measured skin, hair and nail parameters compared with placebo. The caveats matter: it is a single trial, carried out with the ingredient's manufacturer, and it has not changed the regulatory picture. I see it as interesting early science about an ingredient, not a basis for promises.
A plate I like for hair and nail friendly foods: eggs, nuts, seeds and salmon. Illustrative image
Keratin vs biotin vs collagen for hair
These three get muddled all the time, so here is the short version:
- Keratin is the protein hair is made of, but as a swallowed ingredient it has no established hair role.
- Biotin is a B vitamin that contributes to the maintenance of normal hair and skin.
- Collagen is a different structural protein, abundant in skin and connective tissue rather than hair. We compare the two properly in biotin vs collagen for beauty.
If you are choosing between them for hair and nails, the nutrients with recognised roles are the dependable backbone, whatever protein name is on the front of the box.
An honest word on expectations
The evidence is clearest where intake has been low, not for transforming hair that is already healthy. A review by Patel, Swink and Castelo-Soccio notes that, although biotin is heavily marketed for hair and nails, the benefit in studies is mostly seen in people with an underlying shortfall or specific condition. A clinical review by DiBaise and Tarleton adds that nutrient gaps showing up in hair, skin and nails are uncommon in generally healthy, well-fed people and tend to appear with poor intake or absorption problems. Hair grows roughly a centimetre a month and a fingernail takes around six months to grow out, so give any routine at least three months before judging it.
Food sources worth knowing
- Biotin: eggs (especially the yolk), nuts, seeds, salmon and sweet potato.
- Zinc: meat, shellfish, dairy, beans, chickpeas, pumpkin seeds and wholegrains.
- Selenium: Brazil nuts, fish, eggs, meat and some wholegrains. Just one or two Brazil nuts can provide a large amount, so there is no need to eat handfuls.
- Protein overall: since keratin is built from amino acids, eating enough protein matters as much as any single nutrient.
Forms and typical amounts
Hair and nail products come as tablets, capsules, gummies and powders. Where hydrolysed keratin is included, studies have used around 500 to 1,000 mg a day, though there is no established dose because it is not the recognised active. For the nutrients that are, look for clearly declared amounts of biotin, zinc and selenium rather than a megadose of everything. Our Biotin, Zinc and Selenium tablets provide 10,000mcg biotin, 10mg zinc as bisglycinate and 55mcg selenium as selenomethionine per two-tablet serving, vegan and formulated in the UK. If you are wondering about biotin amounts specifically, see how much biotin you need.
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How to choose, and who might consider them
- Check which nutrients are inside and in what amounts, rather than relying on the word keratin.
- Avoid doubling up: if you already take a multivitamin, add up the zinc and selenium across everything.
- If you are vegan, check whether the product contains wool or feather-derived keratin.
- They suit people whose diets may be low in these nutrients, or who simply want a steady routine for hair and nails alongside good food.
For nails in particular, our guide to what supports normal nails goes into more detail.
A few cautions worth knowing
High-dose biotin can interfere with some laboratory tests, including certain thyroid and heart-marker assays, and give misleading results. Tell your doctor or the person taking your bloods that you take biotin, as they may ask you to pause it for a few days first. Zinc and selenium both have upper limits: the NHS advises not taking more than 25mg of zinc a day from supplements, and that 350mcg or less of selenium a day from supplements is unlikely to cause harm. Stick to label amounts and avoid stacking several products that contain them. If you are pregnant or breastfeeding, take regular medication or have a health condition, check with your GP or pharmacist first. Our supplement guides hub has more practical reading.
Frequently asked questions
Do keratin tablets actually contain keratin?
Usually not in a meaningful amount. Most are nutrient formulas built around biotin, zinc and selenium. Some contain hydrolysed keratin, typically from wool or feathers.
Are keratin tablets the same as salon keratin smoothing?
No. Salon keratin smoothing is applied to the outside of the hair and sealed with heat. A tablet is digested like any other protein and cannot coat the hair.
Is keratin, biotin or collagen better for hair?
Biotin, along with zinc and selenium, has a recognised role in maintaining normal hair. Keratin and collagen are structural proteins without a recognised hair role as supplement ingredients.
How long do keratin tablets take to work?
Hair and nails grow slowly, so allow at least three months of consistent use before judging any change. The effect is most noticeable where intake was previously low.
Are keratin tablets vegan?
Nutrient formulas often are, but products containing hydrolysed keratin usually use sheep's wool or feathers, so check the label.
Our pick for this guide
Ready for a simple hair, skin and nails routine?
10,000mcg biotin, 10mg zinc bisglycinate and 55mcg selenium as selenomethionine per two-tablet serving, vegan. Zinc and selenium contribute to the maintenance of normal hair and nails. A food supplement, not a replacement for medical advice.
From £9.50 · 60 tablets, one month
Shop Biotin Zinc Selenium →Sources
- EFSA Panel on Dietetic Products, Nutrition and Allergies, 2012, scientific opinion on a keratin-based combination and maintenance of normal hair, PMC13093101 (DOI 10.2903/j.efsa.2012.2808)
- Tursi and colleagues, 2024, oral keratin hydrolysate and skin, hair and nail parameters, randomised placebo-controlled trial, PMC11743286 (DOI 10.1111/jocd.16626)
- Patel, Swink and Castelo-Soccio, 2017, a review of the use of biotin for hair loss, PMC5582478 (DOI 10.1159/000462981)
- DiBaise and Tarleton, 2019, hair, nails and skin: differentiating cutaneous manifestations of micronutrient deficiency, PubMed 31144371 (DOI 10.1002/ncp.10321)
You can find more of our guides on the Pure Vitamins UK home page.
Warmly,
Dr. Miron, Founder of Pure Vitamins UK
This article is for general information and education. Food supplements are not a substitute for a varied, balanced diet and a healthy lifestyle, and this is not medical advice. If you have symptoms or a health condition, speak to your GP or pharmacist.
